Repair or Replace ? well it's 5k plus,plus,plus (as it goes with old 30+ year engines) versus 13 k-15 k (Approx-25 Hp with sail drive).
I love these older engines but being raw water
cooled and 30 -40 years old can lead to issues!
Express (Volvo Penta, Mercruiser and more - Marine Parts Express - engines, outdrives, propellers
) have a very good easy site with manuals
pricing etc with in a few clicks, you can shop around for cheaper parts for sure but these guys pricing is mid range and usually helpful